1. Field of the Invention
This invention relates to an optical-fiber environment variable apparatus, an optical-fiber extracting apparatus, and an optical-fiber extracting system in which one specific optical fiber may be extracted from a large number of optical fibers at remote sites.
2. Description of the Prior Art
FIG. 5 is a diagram showing a state of optical fibers installed for communication.
The optical fibers 1 are passed from repeater to repeater (not shown) which are mounted at intervals of about 2 km from a communication equipment 3 in facilities 2. Between the repeaters, manholes 4 are provided at intervals of L (about 250 m) for maintenance and inspection of the state of installed fibers.
One cable with a diameter of 5.5 mm forms a fiber bundle including 3,000 pieces of optical fibers 1. Further, 10 to 20 pieces of cables are disposed in a cable duct.
In works of removing an unnecessary optical fiber from a large number of optical fibers 1 (1A, 1B, . . . , IN) which have already been installed, or diverging an optical fiber from an already-installed optical fiber cable, or shifting an optical fiber to another place due to the occurrence of difficulty, it is very difficult to detect the target optical fiber out of the large number of optical fibers.
If another optical fiber is erroneously broken during communication, a failure may occur in an online system, resulting in a serious effect on society.